Lubricating oil



No Drawing.

Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE,

KENNETH G. MACKENZIE, OF WESTPORT, CONNECTICUT, ASSIGNOR TO THE TEXASCOMPANY, OF NEW YORK, N. Y., A. CORPORATIQN DELAWARE LUBRICATING- OILThis invention relates to lubricating oils and more particularly tolubricatmg 0118 which are compounded, having hydrocarbon oils orderivatives thereof as a base.

-mark'ed degree the power consumption costs by reducing the frictionalresistance to: be

' overcome upon starting the motore or journal and during the operationthereof.

These low viscosity oils must, however,

have certain properties or characteristics to adapt them to the servicefor which they" are intended. The viscosities of the oils should be aslow as possible, consistent with flash point for theconditions underwhich they are to be used. The oils must be sufliciently adherent toremain on the surfaces of the metals under severe conditions of service,and must have sufiicient body to act as cushions between the metallicsurfaces, even when the parts are at rest. more, the oils must have thatproperty known as oiliness.

7 These properties have been secured in high degree by compounding anoil or other liquid of the lowest possible viscosity with anothersubstance having high adhesive or adherent properties, such as lard oil,in the proportion of 10% lard oil to 90%of the low viscosity oil orother liquid. It has also been suggested that palm or castor oil,metallic soaps, and oils-treated with sulphur or oxygen might in certaincases be utilized.

I have found that a highly desirable prod uct of extremely lowviscosity, which has the properties of adhesiveness and extremeoiliness, can be made by compounding with the low viscosity baseproduct, a relatively such as'electric railway Further- 1930. Serial No.467,628.

small amount of another product which will supply the adhesiveness,required to insure constant adherence of the lubricant to the bearingsurfaces. Because of the excellent lubricating value of the addedproduct, less of it ordinarily need be added than of the f lard oilheretofore used in order to produce added product is 811- oils proposedby other investigators, and on this account the ultimate product can belowered able to a larger market.

cost of the final and thus .made avail- In United States Patent N 0.1,705,298 issued jointly to me and Raymond Haskell on March 12, 1929, wehave described a lubricating oil comprising a hydrocarbon oil andoxidized parafiin wax. We found that the addition. of a small amount ofoxidized p'arafiin wax to the usual hydrocarbon lubricating oil producedvery beneficial effects. The oxidized paraflin wax which is used incompounding our lubricating oil, as described in Patent No. 1,705,298,is produced by blowing crude or refined wax with air at an elevatedtemperature. A change takes place in the chemical characteristics of thematerial, acidity developing not only as evidenced by the increasingacidity of the material itself, but also by the fact that some volatileacids may be condensed from the air after it has passedthrough the hotmaterial. In addition to these,-however, certain saponifiablebodies oresters are formed, apparently from condensation of acids and alcoholsproducedby the oxidation. These esters'are found to differ from thesaponifiable oils and fats in that they do not readily saponify whentreated with aqueous alkali solution but require treatment with analcoholic solution of alkali to efi'ect saponification.

Upon separation of the constituents of the complete pense involved in'oxidized paraflin wax and compounding wax the material is heated whileexposed to a current of air until practically complete oxidation takesplace. The procedure yields a product which usually has veryunsatisfactory properties rendering'it unsuitable for compoundingwithmineral oils due to the fact that the high oxidation products aredark colored gummy materials insoluble in hydrocarbon oil. To produce aproduct suitable for compounding, I depart from the ordinary method and,while carrying the re- Y action to a fairly definite point as may beevidenced by the acid value of the product, discontinue it before thereis any substantial formation of the gumlike products of a more prolongedoxidation. 1 of about 40 may considered the upper limit to which thereaction may without the formation of gums, I prefer to only carry theoxidation to an acid'value of about 35 which insures the completeabsence of gummy constituents. I

At the same time the quantity of unoxidized wax' or of little oxidizedwax will usually be sufficiently low that the oils comounded with suchoxidized wax product I will have a low pour test. On the other hand ifthe amount of little oxidized wax is objectionable from the standpointof producing the particular service portion of esters.

too high a pour test for desired, this may readily be overcome bysweating the oxidized product to any desired degree to remove thecompounded oils with higher melting portions thereof.

The following is a Specific example of a method which has been foundsuitable in the oxidation of paraffin wax ished product having asufliciently large pro- .A charge of 50 pounds of paraifin wax ismaintained at a temperature of from'295 to 300 F. in an enameled vesselwhile air is introduced in fine streams at the bottom of the vessel. Therate of introduction ofthe air is dependent upon the degree ofdistribution and contact which is obtained with the reaction materials.The oxidation is allowed to proceed for a period of about 48 hoursduring which time there is a lossof from 7% to 10%- in the weight of thecharge due to volatilization products being carried off with the airstream.

A typical sample of material produced by While an acid valuebe safelycarried to produce a fin-- this treatment has the followingcharacteristics:

Acid number 39.8 Total saponification number 170.5 Neutralsaponification number 130.7 Melting point -1 107 F. Neutralsaponification number 3.28

(Acid number) Another sample of the same material was treated first withalkali to neutralize the free acid and then treated with methyl ethylketone in which the parafiin wax is, for practical purposes, insoluble.The following re-.

sults were obtained:

Per cent Free acid 'Material insoluble in methyl ethyl ketone(unsaponifiable material, mainly wax) Material soluble in methyl ethylketone (saponifiable material, mainly esters) 60.8

It will be observed from this data that the oxidized wax contains alarge amount of saponifiable material and comparatively little unchangedwax.

The aforementioned method of oxidizing paraffin wax is given for thepurpose of illustration only, and any other process may be used whichwill produce an oxidized wax containing a large amount of saponifiablematerial and comparatively little unchanged wax, as for example, theprocess described in the patent to J. R. Scanlin No. 1,668,871 dated May8, 1928.

According to the present invention I prefer to use a lubricating oilstock derived either from petroleum or the-products of distillation ofcoal or shale that has the lowest possible viscosity for the conditionsunder whichthe machine operates; that is,"thelowest viscosity that isobtainable with the requisite flash point to withstand the temperatureprevalent duringv use.

The lubricating oil stock may Iconsist of an oil having in general thecharacteristics o lubricant. The flash point should be above 225230 F.and the viscosity of the stock is v preferably within the range of 35 to45 seconds (Saybolt) at 100" F. The finished product is then compoundedwith a small proportion of oxidized paraflin wax containing a largeamount of saponifiable material and comparatively little unchanged wax.In most instances a compounded producthaving a viscosity of about 60seconds or less at 100 F. (Saybolt) and containing from 2%5% of the waxwill give results which are substantially equivalent to those obtainedwith an oil compounded with about 10% of lard oil, but under somecircumstances as much as 15% of wax may be used, it being understoodthat the amount of wax may be varied as circumstances may require.Ordinarily an oil compounded with from 2%- 3% of oxidized paraflin waxand having a p viscosity of 45 seconds or even less at 100 F. (Saybolt)will be satisfactory. While I have thus specifically described myinvention, various modifications thereof 1 may suggest themselves tothose skilled in the art and I desire therefore to be limited only asindicated in theappended claims.

What I claim is: 1; A lubricating oil for heavy machinery consisting ofat least 95% of 'a hydrocarbon oil having a viscosity considerably lowerthan that normally used for suchpurposes and within the range of from 37seconds to V 6O seconds (Saybolt) at 100 F. and from 2% 2 to 5%ofoxidized paraflin wax which has been oxidized in such manner as tocontain a large proportion of saponifiable material. 2. A lubricant forrailway journals and bearings comprising a mixture of the hydrocarbonoil remaining after distilling off about of the lighter constituents ofkerosene and having a viscosity within the range of from 37 seconds to60 seconds Saybolt) at 100 F. and from 2% to 5% of oxidized parafiin'wax which has been oxidized in suchmanner as'to contain a largeproportion of saponifiable material. 7

3. A lubricant for railway journals and bearings consisting of from to98% of 35 a. hydrocarbon oil having a viscosity of approximately 45seconds (Saybolt) at 100 F. and from 5% to 2% of oxidized paraflin waxwhich has been oxidized in such manne'r as to contain a large proportionof saponi- 40 fiable material. v In witness whereof I have hereunto setmy had this 7th day of July,-'1930.

KENNETH G. MACKENZIE.

